This kind of flow analytics are pretty new IMHO. C# supports these e.g. for nullable checks. But I think Java and C# are designed a bit too early for having the

This kind of flow analytics are pretty new IMHO. C# supports these e.g. for nullable checks. But I think Java and C# are designed a bit too early for having these kind of flexibility with the variable type. Also consider that changing the type also has other consequences like invoking other virtual methods (e.g. C# new operator on methods) which can be confusing because a type change above is not explicit. PS: just came to my mind: that is a breaking change (in C#) due to the new operator exanple. Will never come (for C#). Maybe Java does not have this issue but most likely they have a similar problem This is an awesome feature for typescript. Love their work there.